Public bug reported: == Comment: #0 - JENIFER HOPPER <[email protected]> - 2018-07-12 11:41:50 ==
---Problem Description--- We would like to request the following simple qemu patch be applied because it can provide significant performance improvements for Power9 KVM guests that benefit from 2MB THP usage: commit 0c1272cc7c72dfe0ef66be8f283cf67c74b58586 osdep: powerpc64 align memory to allow 2MB radix THP page tables This allows KVM with the Book3S radix MMU mode to take advantage of THP and install larger pages in the partition scope page tables (the host translation). -- For instance, when THP is enabled I measured a 10% throughput improvement with this patch for a full system P9 Radix guest running the SPECjbb2005 workload. Contact Information = [email protected] ---uname output--- Linux perfwsp6 4.15.0-20-generic #21-Ubuntu SMP Tue Apr 24 06:14:44 UTC 2018 ppc64le ppc64le ppc64le GNU/Linux Machine Type = 8335-GTH ---Debugger--- A debugger is not configured ---Steps to Reproduce--- Run a workload that benefits from THP usage in a P9 KVM guest. ** Affects: qemu (Ubuntu) Importance: Undecided Assignee: Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) Status: New ** Tags: architecture-ppc64le bugnameltc-169712 severity-high targetmilestone-inin1804 ** Tags added: architecture-ppc64le bugnameltc-169712 severity-high targetmilestone-inin1804 ** Changed in: ubuntu Assignee: (unassigned) => Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage) ** Package changed: ubuntu => qemu (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1781526 Title: Ubuntu18.04 - qemu patch to align memory to allow 2MB THP To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1781526/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
